L Hoyte1, P Ratiu. 1. Department of Obstetrics and Gynecology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA. lennox@bwh.harvard.edu
Abstract
OBJECTIVE: Magnetic resonance imaging techniques have improved the study of female pelvic dysfunction. However, disagreements between magnetic resonance measurements and their derived 3-dimensional reconstructions were noted. We tested the hypothesis that these discrepancies stemmed from variations in magnetic resonance acquisition angle. STUDY DESIGN: Images from the pelvis of the Visible Human Female (a thinly sliced cadaveric image data set) were obtained. Slices in the axial plane were rotated around pivot points in the pelvis to yield a set of similar-appearing para-axial images. A parameter that described the maximum anterior-posterior dimension of the levator hiatus was defined. This levator hiatus parameter was measured on all of the rotated images and compared with an expected value that was calculated from trigonometry. The levator hiatus was also measured on a group of similar-appearing slices rotated slightly around a defined point. RESULTS: In 1 group of slices, expected levator hiatus variation was 1.5 to 6.1%, whereas measured variation was 4% to 15%. Among the similar-appearing rotated slices, 4.8% to 16.0% variations were seen in the levator hiatus. CONCLUSION: Identical measurements made on radiologic images can vary widely. Slice acquisition must be standardized to avoid errors in data comparison.
OBJECTIVE: Magnetic resonance imaging techniques have improved the study of female pelvic dysfunction. However, disagreements between magnetic resonance measurements and their derived 3-dimensional reconstructions were noted. We tested the hypothesis that these discrepancies stemmed from variations in magnetic resonance acquisition angle. STUDY DESIGN: Images from the pelvis of the Visible Human Female (a thinly sliced cadaveric image data set) were obtained. Slices in the axial plane were rotated around pivot points in the pelvis to yield a set of similar-appearing para-axial images. A parameter that described the maximum anterior-posterior dimension of the levator hiatus was defined. This levator hiatus parameter was measured on all of the rotated images and compared with an expected value that was calculated from trigonometry. The levator hiatus was also measured on a group of similar-appearing slices rotated slightly around a defined point. RESULTS: In 1 group of slices, expected levator hiatus variation was 1.5 to 6.1%, whereas measured variation was 4% to 15%. Among the similar-appearing rotated slices, 4.8% to 16.0% variations were seen in the levator hiatus. CONCLUSION: Identical measurements made on radiologic images can vary widely. Slice acquisition must be standardized to avoid errors in data comparison.
Authors: Shaniel T Bowen; Arijit Dutta; Krystyna Rytel; Steven D Abramowitch; Rebecca G Rogers; Pamela A Moalli Journal: Int Urogynecol J Date: 2022-04-08 Impact factor: 1.932
Authors: Lennox Hoyte; Linda Brubaker; Julia R Fielding; Mark E Lockhart; Marta E Heilbrun; Caryl G Salomon; Wen Ye; Morton B Brown Journal: J Magn Reson Imaging Date: 2009-08 Impact factor: 4.813